We describe a case of
aldosterone-producing
adrenocortical adenoma (APA) associated with a probable post-operative adrenal crisis possibly due to subtle autonomous
cortisol secretion. The patient was a 46-year-old female who suffered from severe
hypertension and
hypokalemia. CT and MRI scans revealed a 2-cm diameter adrenal mass. The patient's plasma
aldosterone level was increased, and her plasma
renin activity was suppressed, both of which findings were consistent with APA. Cushingoid appearance was not observed. Morning and midnight serum
cortisol and plasma
adrenocorticotropic hormone (
ACTH) levels were all within the normal range. Her serum
cortisol level was suppressed to 1.9 microg/dl as measured by an overnight 1-mg
dexamethasone suppression test, but was incompletely suppressed (2.7 microg/dl) by an overnight 8-mg
dexamethasone suppression test. In addition, adrenocortical scintigraphy showed a strong uptake at the
tumor region and a complete suppression of the contra-lateral adrenal uptake. After unilateral
adrenalectomy, she had an episode of adrenal crisis, and a transient
glucocorticoid replacement improved the symptoms. Histopathological studies demonstrated that the
tumor was basically compatible with APA. The clear cells in the
tumor were admixed with small numbers of compact cells that expressed 17alpha-hydroxylase, suggesting that the
tumor was able to produce and secrete
cortisol. In addition, the adjacent non-neoplastic adrenal cortex showed cortical
atrophy, and
dehydroepiandrosterone sulfotransferase immunoreactivity in the zonae fasciculata and reticularis was markedly diminished, suggesting that the hypothalamo-pituitary-adrenal (HPA) axis of the patient was suppressed due to neoplastic production and secretion of
cortisol. Together, these findings suggested that autonomous secretion of
cortisol from the
tumor suppressed the HPA axis of the patient, thereby triggering the probable post-operative adrenal crisis. Post-operative adrenocortical insufficiency should be considered in clinical management of patients with relatively large APA, even when physical signs of autonomous
cortisol overproduction are not apparent.